The present invention relates to bulldozers or the like having transversely extending material moving blades, and more particularly to an improved and simplified mechanism for automatically shifting the blade laterally as the blade is angled, thereby permitting the use of a blade which is shorter than conventional angling blades.
It is known to provide in bulldozers or similar types of earthworking machines a pusher frame of C-shaped configuration which fits between the track frames or surrounds the front end of the tractor. The rear ends ofthe two arms of the C-shaped frame are pivotally connected to the sides of the tractor to permit raising and lowering of the C-shaped frame about a transverse axis thereby permitting lowering of the blade to a working position on the ground and raising of the blade for transport to another location.
Conventionally, the load handling blade is mounted on the earth moving equipment by means of a central swivel joint, one part of which is attached to the rear of the blade and the companion part is attached to the pusher frame of the earth moving equipment so as to permit up and down movement, pivotal side or angular movement, and edgewise tilting movement of the blade. Various problems occur in the design of such mechanisms, particularly when utilizing the angling provision of the blade. Standard angling dozer blades are considerably wider than the track frames in order to cut a path for both tracks to run in when the blade is angled. This creates a problem when utilizing the blade to cut into a side bank as follows.
When the dozer blade is angled to cut into a bank, one end of the blade takes substantially all of the load which causes the tractor to be forced out of its intended path. This necessitates corrective steering by the operator to keep the tractor on course. To reduce the amount of leverage which twists the tractor when a bank cut is being made, the end of the blade should be in line with the side of the tractor. This is not possible with conventional angling blades because the blade is substantially wider than the tractor to cut a path for the tracks when the blade is angled. Thus, there has been a need for a mechanism having the ability to automatically shift the blade laterally to permit a blade which is shorter than conventional angling blades.
One type of prior art construction provides a guide rail on the back of the blade which has spaced holes for receiving a locking pin, and a portion of the blade frame connection is slidable in the rail. The blade is shifted laterally by removing the locking pin and adjusting it to a desired position and then relocking the pin. Thus, the conventional type arrangements for laterally shifting the blade require complicated mechanical structure, multiple operational steps, and do not permit lateral adjustment of the blade without disconnecting the blade from the support.
These disadvantages of present bulldozer constructions have resulted in the blade shifting construction and controls therefor of the present invention which effectively eliminates the above difficulties of the prior art.